People has more and more needs for liquid crystal display products of Advanced Super Dimension Switch (ADS) technology, and have an increasingly high requirements of control on power consumption of products as well, and this requires that aperture ratio of pixel units should reach a higher level to reduce the power consumption. In addition to control on processes, improvement of design has become an important way to increase aperture ratio.
In a conventional ADS mode liquid crystal display product to which common electrodes are incorporated, the common electrodes are connected to common electrode lines (e.g. an ITO layer) periodically through via holes, which serves a function of connecting the common electrodes in parallel so as to decrease the resistance. Referring to FIG. 1, in the array substrate as shown, a pixel unit A is defined by enclosing of a gate line 101, two longitudinal data lines 102 and a common electrode line 103, and protrusive parts on the gate line 101 functioning as gate electrodes extend toward corresponding pixel units driven by the gate electrodes, which results in the result that space on the array substrate cannot be effectively utilized. Furthermore, a via hole B for connecting a source electrode of a thin film transistor to a pixel electrode for each of pixel units is located within a display area of the pixel unit. In order to prevent light leakage, a black matrix (BM, not shown in the drawing) is typically formed on a color filter substrate to provided shield, the color filter substrate is used in conjunction with the array substrate, and the configuration decreases aperture ratio of the pixel units to a great extent, and moreover, due to a precision problem encountered when the array substrate and the color filter substrate are disposed opposite to each other, light leakage at the via hole may be still incurred.
In addition, in the conventional ADS mode product to which common electrodes are incorporated, thin film transistors and a gate line are shielded by a row of black matrix on the color filter substrate over the gate line of the array substrate, this row of black matrix has an irregular shape and does not conform to the row of black matrix on the color filter substrate, which is located over the common electrode line of the array substrate and has a regular shape. As such, horizontal stripes will occur in a finally finished product, and in turn, luminance difference between adjacent rows leads to abnormal display on the whole screen.